Vertical heat exchanger



June 28, 1938. G. TREPAUD VERTICAL HEAT EXCHANGER Filed May 2 OOO lNVENTOFY- G'EORQEs T EPHUQ BY: 6

HTTORNEY Patented June 28, 193 8 UNITED STATES VERTICAL H AT EXCHANGER Georges Trpaud, La Rochelle, France Application May 2, 1936, Serial No. 77,462

In France May 7, 1935 ,1 Claim.. (01. 357-224) The heat exchangers or Vaporizers as used at present in the apparatuses for the production of cold are of cliiferent systems according to the amount of heat to be extracted. For the small I 3 powers, the brine cooling device is "constituted by a bundleof double concentric tubes which are horizontally disposed, the brine circulating in central pipes, whilst the cold producing 'medium, ammonia for instance, passes through the annular space existing between the walls of the concentric tubes.

As regards the great power apparatuses, use is made either of the apparatuses comprising a brine container, or of apparatuses comprising a cylindrical cooler. In the first case, there is disposed in a tank a vaporizing coil which is placed horizontally and which is immersed in the brine contained in the vat; the circulation of the brine along the walls of the coil is most often obtained. by meansof a screw operated'by a devicesituated outside the vat. 1 In the apparatuses with cylindrical cooler, the vaporizing part is constituted by a horizontal tubular bundle disposed in a cylindrical tank; plates, situated at a certain distance from'the bottoms of said tank, are connected through tubes and by means of baflle plates, disposed in every end chamber, increase the ooefiicient of exchange betweenthe two fluids. The brine is set in circulation in the tubes, whilst the cold generating fluid circulates around the tubes in the tank surrounding the same. The results obtained with these two sorts of apparatuses are not always satisfying.

The heat exchanging evaporating device forming the subject matter of the invention, being disposed vertically, the circulation of the fluids takesplace much more freely than in the horizontal apparatuses and in a much more active manner, whence a much more rapid exchange of heat results. s

The said apparatus is essentially constituted by a vertical. tubular body, surmounted by a 'steam dome and provided at its lower part with 45 a liquid collector. The cylindrical bodyv is connected to the brine circuit through the usual apparatuses and the tubular bundle with the freezing liquid compressor or with any other similar machine or fume sucking device.

One of the mainfeatures of the invention consists, moreover, in the fact that the tubular bundle or nest is "combined with walls so arranged in the tubular body containing the-same that the fluid circulating in this space follows a helical movement along the tubes.

e In the accompanying drawing given byway of example only:

Fig. 1 shows in vertical section an. evaporator constructed according to the invention.

Fig. 2 is a horizontal section of the tubular 5 bundle or host.

Fig. -3 shows diagrammatically the path followed by thebrine in the-tubular body.

Fig. 4 is an elevation and Fig. 4a a plan view of one of the 'baflles.

. Fig. 5 is a. horizontal section showing a modifled form of construction.

The vertical evaporator with accelerated circulation for the production of cold consists in three parts: a tubular body in which the exchange of heat takes place, a dome for collecting the fumes or vapours of the cold producing liquid, ammonia for instance, and a collector in' which the liquid is collected.

The'tubular body is constituted by a vertical ferrulel, closed by two plates 2, 3, in which are beaded the ends of the tubes 4 of the bundle. The tubes 4 are of small diameter in order to increase the surface of contactof the fluids. In the central part of the plates 2, 3 is secured the end of a tube of large diameter 5. The ferrule l is provided at its lower and upper parts with pipes 6, 1 allowing the same 'to be connected to the circuit of the brine.

The brine circulates around tubes 4 in the annular spaces comprised between baffles 8, 9 and 9, 8, etc.

During its passage between two bailles, the brine strikes the external surface of the evaporating tubes 4 in the contact with which the exchange of heat as looked for takes place. The rate of circulation about the wall of the tubes is accelerated by the baflles.

The long course of the brine around the tubes containing the cold producing liquid allows the same to absorb the calories accumulated during the use in causing a vaporization of the cold producing liquid.

The opening l0, provided in every baille, is shifted off relatively to the following one accord-- ing to an angle of about so, that the brine will have imparted thereto a continuous movement which can be compared to a helical move-- ment about the central tube 5. Fig.- 3 shows clearly the circuit efiected by the brine between the baflles. The opening l0 instead of being a radial one could be a segmental one and be diametrally opposed when the baflles are mounted so as to impart to the brine a coil motion. It

must be understood that the size of the opening 55 vail in every case. Thus, for instance, the said openings can be of 120 when the baiiies are in be very close together.

The spacing of the baflies is maintained, on the one part, by the part 8 bent at right angle (Fig. 4) and, on the other hand, by means of tubularstruts ll, disposed about the tubes 4; a few struts will sumce.

The result obtained with. the baflies is substantially as satisfying as the one which is obtained by means of an endless screw; however with this advantage that the construction is more simple and consequently less expensive.

The tubular body is surmounted by a dome l2 secured by a strap l3 and provided internally with a deflector lldisposed in front of a tubular bundle. The said deflector is formed of two frustums connected together by means of their small bases; the same is intended to stop the boiling liquid and to direct the same towards the central tube 5 so that it can be taken over by the liquid circuit circulating in the bundle.

The vapour which is carried along with the boiling liquid is directed towards the upper part of the dome in passing through the baiiles a provided with holes drying the same entirely in stopping the drops of liquid which might have been driven along by the same. The said baflles a are also used as struts for supporting the suction pipe I5 of the compressor. The steam supply is provided with a sprinkler l6 dividin the steam and retaining the last liquid particles driven along by the steam.

The tubular body is formed at its lower part by a collector'i'l in the central part of which is disposed a separator l8 provided with ports l9 in connection with an exhaust pipe 20. The said separator is adapted to stop the oil carried along by the ammonia in being collected under the separator, thereby insulating the same from the circuit of the cold producing fluid. The said oil can be removed very easily through the exhaust pipe 20.

The cold producing fluid returns to the tubular body through the pipe 2| by means of a tap provided with a float automatically regulating the height of the liquid contained in the said tubular body. The collector i1 is also in connection with the tank containing the float tap to can be adapted to the conditions which prethrough the pipe 22. The vapours or fumes which can be produced in the 1iquid tank are exhausted through the pipe 23 in the direction of the dome.

0n the upper part of the dome is disposed a tube 24 allowing the exhaust of air when the apparatus is set in motion It is 'to be observed that in the above described evaporator, the cold producing fluid circulates in the tubular bundle and the brine passes around the walls of the tubes of the said bundle.

Finally, it must be observed that the central tube 5 used for the return of the currents of thetubular bundle could be replaced by several tubes 25, as. shown in Figure 5.

The embodiment which has been described and which is represented has of course been given by way. of example only and it will be understood that its details may vary without departing from the principle of the invention.

I claim,

A vertical heat exchanger comprising a vertical casing, upper and lower tube sheets mounted in said casing and dividing the same in an upper chamber, a middle chamber and a lower chamher, a vertical central tube of large diameter axially disposed in the-casing between the said tube sheets and connecting said lower chamber to said upper chamber, vertical tubes of small diameter disposed in the annular space formed between the said casing and central tube and also connecting the lower chamber to the upper chamber, means for admitting a liquid reiriger-.

ant into said central tube, means for withdrawing vapors from said upper chamber, means for admitting a fluid to said annular space and for withdrawing said fluid from said annular space, baflle plates mounted in said annular space so as to provide a substantially helical path for the fluid, and a double-frustrum shaped deflector -mounted in the said upper chamber, the lower part. of the said deflector overlying the upper ends of the said vertical tubes of small diameter so as to reject liquid projected out of said tubes and direct it into said central tube, and the upper part of said deflector guiding liquid separated in said 'upper chamber also into said central tube.

GEORGES TREPAUD. 

